1. Field of the Invention
The present invention relates to a vehicle safety device control apparatus, and more particularly to an apparatus for controlling a plurality of vehicle safety devices.
2. Prior Art
Air bags and preloaders are representative examples of the various vehicle safety devices that have been developed to protect passengers from the shock of vehicle collisions. These devices can be used independently. However, arrangements are known in which the safety of passengers involved in a vehicle collision is further ensured by using two types of safety devices together, for example by providing the driver's seat with an air bag device and a preloader device that are both activated when it is sensed that the vehicle is in a collision.
However, such an arrangement in which multiple vehicle safety devices of different types are used selectively together gives rise to the following problems. Normally the optimum timing used to trigger an air bag device is determined on the basis of the results of collision tests in which passengers are not restrained. When a preloader device is being used together with an air bag device, for example, a passenger is restrained by the preloader device when a collision occurs. As a result, displacement of the passenger's head is delayed compared to when a passenger is not thus restrained. This gives rise to a clear risk that the air bag will have started to deflate by the time the passenger's head contacts the air bag.
It is possible that this problem could be resolved by employing a multi-point sensor system, for example, but this is disadvantageous owing to the fact that costs would be increased by the need for many more sensors required together with the need to be able to alter the characteristics of the sensors.